时光微凉人心太脏

Translated into 'the time has a slight chill, the human hearts are filthy'. '时光微凉'(shíguāng wēi liáng) suggests an emotionally cooling period, and '人心太脏'(rénxīn tài zāng) refers to people getting too selfish, evil or negative. Altogether it could mean that the innocence of time cannot withstand the filthiness of human nature.